Davidsonia - A Journal of Botanical Garden Science

Davidsonia Volume 21, Number 1, 2011

Wed, 14 Dec 2011 13:39:01 -0800

Abstract or Summary:

A Journal of botanical garden science.

Rare mosses from siliceous regions in the Northern Rockies, Alberta, Canada: additions and significance

Wed, 14 Dec 2011 13:24:22 -0800

Abstract or Summary:

This study documents the occurrence of 62 rare mosses from siliceous regions within the northern Canadian Rocky Mountains. Ten species are reported as new to Alberta, and an additional three species are confirmed for the province. Additional records are documented for 49 mosses. The high diversity of rare silicolous species emphasizes the importance of this siliceous flora in the province. In addition, the large numbers of new occurrences significantly add to the knowledge of rare moss distribution in Alberta and diminishes the support for a rare species “hot spot” centred in the northern Rockies. The numerous additional records underscore the importance of inventory work for use in monitoring and environmental assessment.

Editorial - Volume 21, Number 1

Wed, 14 Dec 2011 13:20:28 -0800

Abstract or Summary:

Editor, Iain Taylor writes about the importance of natural history research.

Davidsonia Volume 20, Number 2, 2010

Mon, 13 Dec 2010 17:05:51 -0800

Abstract or Summary:

Davidsonia - a Jounal of Botanical Garden Science

Mangrove and Brazilian pepper in the garden: A case study of vegetation change over 80 years.

Mon, 13 Dec 2010 16:38:10 -0800

Abstract or Summary:

Brazilian pepper (Schinus terebinthefolia) is an aggressive exotic shrub in South Florida, which invades disturbed areas and often creates dense monocultures. As part of management efforts at Montgomery Botanical Center, we investigated a disturbed habitat with both Schinus terebinthefolia and native mangrove vegetation, on a 12 hectare landsite that was initially cleared and has been left fallow since at least the 1950s. We examined relative density and spatial distribution of mangrove and S. terebinthefolia, in order to explore hypotheses about competition between mangroves and S. terebinthefolia. We reviewed archived aerial photographs and conducted a targeted field survey of the interface between the mangrove and Brazilian pepper. Results of the survey and modeling demonstrate that mangroves may sometimes compete successfully with S. terebinthefolia. Intermediate age S. terebinthefolia were not observed at any transect point and seedlings did not produce typical allelopathic effects. In this case mangrove vegetation may compete when dispersed into open areas proximal to Schinus stands. Areas first colonized by mangrove did not support recruitment of Schinus and dense monospecific stands of S. terebinthefolia did not support further seedling recruitment of that species. This may be due to the specific hydrolic conditions and soil dynamics observed in this area. Marl soil, low elevation and constant flux in water level hindered the ability of Schinus to dominate the entire area of the study. Our observations are consistent with observations that early phases of mangrove restoration work are critical to establishing healthy mangrove systems, which are less likely to be invaded by Schinus as mature stands.

Davidsonia - Volume 20, Number 1, January 2010

Fri, 27 Aug 2010 09:23:50 -0700

Abstract or Summary:

Davidsonia - A Journal of Botanical Garden Science

Davidsonia - Volume 19, Number 2, April 2008

Fri, 13 Feb 2009 14:49:21 -0800

Abstract or Summary:

Davidsonia - A Journal of Botanical Garden Science

Editorial - Davidsonia Volume 19, Number 2

Fri, 13 Feb 2009 14:40:28 -0800

Abstract or Summary:

Editor, Iain Taylor writes about man-made and natural disturbances to ecosystems and the need to understand the impacts of these disturbances.

How to grow, propagate and kill some of the native plants in the Kluane region, southwestern Yukon

Fri, 13 Feb 2009 14:35:12 -0800

Abstract or Summary:

During over 15 years of plant ecological research in the Kluane region of southwestern Yukon, our studies required us to grow, propagate, and sometimes kill, native plants for experimental purposes. Here we present observations on germinating, growing, propagating and transplanting some of the common native plant species in the Kluane region.

Impact of a severe flood on canopy composition, tree regeneration, and ground flora of the ... Red River, Canada

Fri, 13 Feb 2009 11:55:17 -0800

Abstract or Summary:

The 1997 Red River flood afforded a valuable opportunity for studying the impact of an infrequent severe disturbance on gallery forests. In 1997 and 2002 we sampled two sites protected and two sites unprotected by a flood control structure near Winnipeg, Manitoba, Canada using three 150 m transects in the lower floodplain (n = 45 quadrats per site). The mature canopy of unprotected sites consisted of Fraxinus pennsylvanica Marsh. and Ulmus americana L. at low cover whereas protected sites contained five tree species. Regeneration data suggest F. pennsylvanica will continue to dominate in unprotected sites, with treefall providing opportunities for pioneer flood specialists like Salix amygdaloides Anderss. Fewer gap openings occurred in protected sites, in which Acer negundo L. and F. pennsylvanica will likely become co-dominants.

Understorey taxa normally able to survive the moderate disturbance associated with seasonal inundation of the lower floodplain of protected sites succumbed to the harsh conditions in the unprotected sites. Many were knocked back or eliminated by 2002, with greater reductions in richness and diversity in unprotected sites. Ruderals were promoted in unprotected sites but most were less prominent by 2002. Although several taxa, e.g., Vitis riparia Michx. and Bidens frondosa L. had significantly higher cover in protected sites by 2002, Xanthium strumarium L. and Polygonum amphibium L. were the only understorey species with significantly higher cover in the unprotected sites. Correspondence analysis indicated flood protection generated differing trajectories, with site differences contributing to variable successional outcomes.

Book Reviews - Davidsonia Volume 19, Number 2

Fri, 13 Feb 2009 11:45:47 -0800

Abstract or Summary:

Senescence processes in plants edited by Susheng Gan, Annual Plant Reviews 26 (2007) Blackwell Publishing
Ltd, Oxford, UK; Ames, Iowa: and Carlton, Australia; and The Physiology of Crop Yield, 2nd Ed. 2006, Robert KM Hay and John R Porter, Blackwell Publishing, Oxford, UK; Ames, IA; Carlton,Australia are reviewed.

Gleanings - Davidsonia Volume 19, Number 2

Fri, 13 Feb 2009 11:44:13 -0800

Abstract or Summary:

Notes on papers (some technical and others less so) that may be of interest.

Davidsonia Volume 19, Number 1, January 2008

Thu, 29 May 2008 16:15:16 -0700

Abstract or Summary:

Davidsonia - A Journal of Botanical Garden Science

Editorial - Davidsonia Volume 19, Number 1

Thu, 29 May 2008 16:14:37 -0700

Abstract or Summary:

Editor, Iain Taylor writes on the need for environmental protection of endangered habits in the face of encroaching human development and a changing climate.

Historical (pre-settlement) ecosystems of the Okanagan Valley and Lower Similkameen Valley

Thu, 29 May 2008 15:04:47 -0700

Abstract or Summary:

A series of maps compare the 1800, 1938 and 2005 ecosystems in the Okanagan and Lower Similkameen Valleys. Much of the gentle slope valley bottom ecosystems have been replaced by urban and agricultural development. Analysis of the areal extent of historical and remaining areas has been done for specific ecosystem types that are important for many species at risk and are themselves ecosystems at risk. These include: Douglas-fir – pine-grass gentle slope; Ponderosa pine – bluebunch wheatgrass gentle slope; water birch – red-osier dogwood wetland riparian shrub; black cottonwood – red-osier dogwood floodplain; the Okanagan River ecosystem; cattail marsh; Idaho fescue – bluebunch wheat-grass grassland; big sagebrush shrub-steppe and antelope-brush – needle-and-thread grass shrub-steppe. For two of these ecosystems, over 90 percent of the original ecosystem has been lost.

Uses of this mapping for conservation of species at risk are presented, including applications to status assessment, quantification of threats, informing restoration projects, and providing data on the importance of the remaining areas of ecosystems that have been severely depleted. The paper concludes that it is important to focus on conservation of ecosystems in order to maintain species at risk.